| 3.1 Outside appearanceA.The end face of foil covered board should be tidy without any delamination and crackle.B. Any bubble, wrinkle, pin hole, deep nick, pitting and glue spot on the copper foil covered face is not allowed. Any color changing or dirty can be easily removed by density 1.02 g/cm3 hydrochloric acid or proper organic solution..C. On laminated face, the defects such as bubble, impressed pitting, nick and glue lack and outer impurity which retard its use are not allowed. 3.2 The foil covered board should meet with the requirements of all items of non electric performance listed at table 2. 3.3 Non performance of insulation basic material after all copper foil removal.3.3.1 On insulation basic material, the pitting, cavity hole, glue lack, white spot, loosen or outer impurity (including solid resin grains) which retard its use are not allowed. The color should be uniform. A little irregular change of color is allowed. 3.3.2 After all copper foils on the foil covered board are removed according to the stipulations on Chapter 3 of GB/T4722, the insulation basic material performance should meet with the stipulation on table |
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